The invention relates to the field of intravascular delivery systems, therapeutic devices, imaging systems and more particularly to a regrooming device for balloon catheters.
In percutaneous transluminal coronary angioplasty (PTCA) procedures, a guiding catheter is advanced until the distal tip of the guiding catheter is seated in the ostium of a desired coronary artery. A guide wire, positioned within an inner lumen of a dilatation catheter, is first advanced out of the distal end of the guiding catheter into the patient""s coronary artery until the distal end of the guide wire crosses a lesion to be dilated. Then the dilatation catheter having an inflatable balloon on the distal portion thereof is advanced into the patient""s coronary anatomy, over the previously introduced guide wire, until the balloon of the dilatation catheter is properly positioned across the lesion. Once properly positioned, the dilatation balloon is inflated with liquid one or more times to a predetermined size at relatively high pressures (e.g. greater than 8 atmospheres) so that the stenosis is compressed against the arterial wall and the wall expanded to open up the passageway. Generally, the inflated diameter of the balloon is approximately the same diameter as the native diameter of the body lumen being dilated so as to complete the dilatation but not overexpand the artery wall. After the balloon is finally deflated, blood flow resumes through the dilated artery and the dilatation catheter can be removed therefrom.
In such angioplasty procedures, there may be restenosis of the artery, i.e. reformation of the arterial blockage, which necessitates either another angioplasty procedure, or some other method of repairing or strengthening the dilated area. To reduce the restenosis rate and to strengthen the dilated area, physicians frequently implant an intravascular prosthesis, generally called a stent, inside the artery at the site of the lesion. Stents may also be used to repair vessels having an intimal flap or dissection or to generally strengthen a weakened section of a vessel. Stents are usually delivered to a desired location within a coronary artery in a contracted condition on a balloon of a catheter which is similar in many respects to a balloon angioplasty catheter, and expanded to a larger diameter by expansion of the balloon. The balloon is deflated to remove the catheter and the stent left in place within the artery at the site of the dilated lesion.
In the design of catheter balloons, balloon characteristics such as strength, flexibility and compliance must be tailored to provide optimal performance for a particular application. An important consideration is the outer diameter of the balloon in its deflated condition. This outer diameter affects the ease and ability of the dilatation catheter to pass through the guide catheter and through the coronary arteries leading to the stenosis, and thus is one of the critical factors to the successful performance of the device and treatment of the lesion.
In order to reduce the outer diameter of the balloon catheter in its uninflated (i.e. deflated) condition, it is common to fold and/or wrap the wings of the uninflated (i.e. deflated) balloon about the inner tubular member. When inflation fluid is applied to the deflated balloon, it causes the balloon wings to unwrap so that the balloon can expand to its full inflated state.
At times, it becomes necessary to regroom the balloon prior to actual use (e.g., introduction into the patient""s body), as for example, after removal of the balloon catheter from its packaging and preparing it. In such an event, it is necessary to reshape the balloon.
The regrooming of the deflated balloon has been achieved by, thus far, for example, the physician or operator in the lab rewrapping the balloon around the tubular inner member by hand; the physician or operator loading the balloon onto the back end of the guidewire currently seated in the patient and using it as support for a regrooming sheath to be slidably fitted over the balloon in an attempt to refold the balloon which may introduce potential risk of damage to the patient""s arteries; the physician or operator using a spare mandrel and a regrooming sheath and fitting the two together for rewrapping the balloon; and refolding the balloon by only using a regrooming sheath without a mandrel which often times causes kinking of the balloon thus making it non-functional or decreasing its performance.
Therefore, what has been needed is a more robust regrooming device suitable for use with balloon catheters and stent delivery systems. The present invention satisfies these and other needs.
The invention is directed to a regrooming device for use with balloon catheters and stent delivery systems, particularly catheter balloons which form wings when deflated. The regrooming device of the present invention comprises a tubular member having a proximal section and a distal section and an inner lumen 31 extending therein configured to slidably receive the deflated balloon so as to refold the deflated balloon. The regrooming device, furthermore, includes a mandrel disposed within the inner lumen of the regrooming device to guide the deflated balloon into the inner lumen so as to be centrally disposed within the lumen. The mandrel has a proximal end and a distal end which is secured to the distal section of the tubular member. The proximal end of the mandrel, preferably, protrudes out of the proximal section of the regrooming device.
The tubular member, preferably has a flared proximal end at its proximal section. The mandrel, preferably, has a curve or bend at its distal end. The curve is secured to the distal section of the tubular member by way of protruding out of an aperture at the distal section of the tubular member, with the curve butting up against the outer perimeter of the distal section of the tubular member.
Alternatively, the mandrel may not have a curve or bend in the distal section, but could be straight and secured to the tubular member with adhesive, a mechanical fastening device or crimping method.
Alternatively, the tubular member forming the regrooming device has an inner lumen defined, at least in part by a cylindrical member. The cylindrical member, may optionally, have a biocompatible fluid in or on its inner surface defining the lumen. The fluid may be either or both a lubricious fluid for facilitating entry and withdrawal of a balloon and a drug to be coated onto the balloon for delivery into the patient.
Alternatively, the regrooming device has a cap at the proximal section of the tubular member. The cap, preferably, has a notch therein for receiving the proximal end of the mandrel. The inner lumen of the tubular member is, at least partially, filled with fluid. The cap provides a liquid-tight seal with the proximal section of the tubular member, containing the fluid within the tubular member. The cap may be removed prior to the insertion of the balloon into the lumen of the regrooming device so that the balloon is coated with the fluid during the regrooming process.
Alternatively, the cap includes a membrane for holding the fluid in place within the inner lumen of the device. The membrane cap may receive a portion of the mandrel therein.
Alternatively, the device may be used for applying or reapplying a coating to a balloon or alternative technology device such as a balloon catheter for stent delivery or an ultrasonic catheter.